The present invention relates generally to handheld cutting tools, and particularly to an improved and reliable handheld tool for reliably cutting lengths of tubing, such as conduit: or the like.
Various types of tubing are widely used in the construction industry. For example, in residential construction, this tubing may typically include copper pipe used to construct water systems and steel conduit used to construct electrical systems. Although in construction, these tubing types are supplied to standard stock lengths, during installation, the tubing must be cut to various different lengths. Hence, an electrician or plumber must make numerous different cuts in a workday during installation.
Known handheld tubing cutters, such as that described in U.S. Pat. No. 5,206,996, issued May 4, 1993, require the user to slip the tool over the tubing length and locate the tool at the precise point where the operator wants to make a cut. The tool is then affixed to the tubing by way of a set screw to retain the cutting tool in place on the tubing length. The tool is then twisted or rotated around the tubing length until the cutting wheel of the tool cuts through the tubing sidewall. Often, the tool may require the operator to manually apply force to the tool such as by squeezing a pair of tool jaws. These manual steps are repeated for every single cut and the steps associated with this style tool not only are monotonous, but also are fatiguing. A fatigued worker may take longer than necessary on a construction project and thus the expense of construction may be increased.
These numerous steps-exemplify one disadvantage of conventional handheld and hand powered cutting tools. Other cutting tools are electrically powered but also have their own particular disadvantages in that they are extremely complex to manufacture, may only be used for one size of tubing, and may not have any self-centering mechanism.
A need therefore exists for a handheld power cutting tool or tubing, conduit or the like which avoids the aforementioned shortcomings. In accordance with an important aspect of the present invention, an improved handheld rotary cutting tool for tubing is provided which includes a rotating cutting assembly having two distinct cutting elements which are mounted on two cutting head assemblies opposite each other around a centerline of an opening in the tool through which the tubing length passes. Each of the cutting head assemblies slidably engages a carrier component rotatably mounted on a base member. Because of the sliding engagement of the cutting carriage and carrier component, the cutting head carriage automatically adjusts itself to the outer diameter of the tubing being cut. Rotation of the base member during operation causes each cutting head assembly to pivot such that a weighted portion thereof swings radially outwardly due to centrifugal force created by the rotation and a cutting portion swings radially inwardly to contact with the exterior surface of the tubing length. As the rotation of the base member continues, the cutting elements cut deeper into the tubing length sidewall. As the rotational speed of the assembly increases, a greater cutting force is exerted on the tubing length.
In another principle aspect of the present invention, each cutting head includes a cutting element carriage in which a cutting element and pressure element, are mounted between two end plates. The centers of the cutting and pressure elements are positioned beneath the center of the cutting head carriage to thereby permit each cutting element to independently center itself within the tool during operation. Each cutting head carriage further slidably engages a carrier member endplate within a recess and is further operatively connected to same by one or more tension springs which assist the cutting carriages along a preselected track of the carriages.
In yet another principle aspect of the present invention, the cutting assembly is mounted within a handheld tool in a body portion thereof. The body portion incorporates a distance measuring means operatively connected to the cutting assembly and is further indexed to the centerline of the cutting assembly so that the measurement means obtains precise lengths of tubing within the tool.
In still another principle aspect of the present invention, the cutting assembly is mounted on a handheld tool body portion which is powered by a drive means. The drive means also drives a deburring roller located in the body portion of the tool. The deburring roller includes a reaming bit having a single radial flute that serves to remove burrs from the tubing cut so that any rough edges remaining on the cut tubing length may be easily removed.
Accordingly, it is therefore a general object of the present invention to provide an improved apparatus for cutting tubular members capable of reliable operation which consistently cut a variety of tubing sizes without an irregular cut.
Another object of the present invention is to provide a cutting assembly for a handheld tool which cuts by way of rotation about a center point of the tool wherein a number of different size tubing lengths can be reliably cut.
Still another object of the present invention is to provide an improved, handheld tubular member cutting tool having a cutting assembly with two cutting heads, each cutting head being mounted on the assembly and adapted for rotation about a center point of the assembly, such that when rotated, portions of the cutting assembly are swung outwardly by centrifugal force such that the cutting elements thereof are brought into contact with the exterior surface of the length of tubing, the cutting elements being mounted in the cutting head beneath the central axis of the cutting head.
Yet another object of the present invention is to provide a handheld apparatus for cutting discrete lengths of tubing or conduit, the apparatus having an opening which receives the tubing or conduit and a cutting assembly which rotates around the opening and which is powered by a drive means located interior of the tool, or interior of the tool body portion, the cutting assembly having multiple cutting heads, each cutting head being disposed opposite anther cutting head and having a cutting element and a roller element, the cutting element contacting the outer surface of the tubing with a cutting wheel portion and the roller element also contacting the outer surface of the tubing, the cutting and pressure elements being slidably mounted on a carrier assembly of the cutting assembly, and further being adapted for movement on a tracking edge of the carrier assembly, the cutting head being the further partially restrained by a biasing means and the cutting and roller elements being disposed in the cutting head generally the center point of the cutting assembly and cutting head.
These and other objects, features and advantages of the present invention will be clearly understood through a consideration of the following detailed description.